There has been a "widespread and significant destruction or loss of evidence" in the so-called Wagatha Christie case, Coleen Rooney's barrister has told the High Court.
The wife of ex-footballer Wayne Rooney is being sued for libel after claiming Rebekah Vardy, the wife of striker Jamie, leaked her private information.
The loss of Mrs Vardy's documents "must be concealment", David Sherborne said.
But Mrs Vardy's barrister described the claim as "completely baseless".
The court has heard that Mrs Vardy's agent, Caroline Watt, lost her phone in the North Sea after it was hit by a wave before Mrs Rooney's team could see WhatsApp messages that could potentially help her case.
Mr Sherborne told the court on the trial's opening day there had been "a concerted effort to ensure highly relevant and incriminating" documents didn't make it to court.
He said a series of "most improbable events" had affected the disclosure of evidence, including Ms Watt's "poor unfortunate phone" falling into the sea "within days" of the court ordering that it should be searched for disclosure.
"What terrible luck," Mr Sherborne said.
In a written submission, he added: "To borrow from Wilde, to lose one significant set of documents may be regarded as a misfortune, to lose two, carelessness, but to lose 10? That must be concealment."
Hugh Tomlinson, representing Mrs Vardy, countered that it had not been suggested "that Mrs Vardy was anywhere near the North Sea at the time" nor that she "knew anything about it".
He added that there was a "credible, ordinary, boring explanation" behind media files on Mrs Vardy's own WhatsApp account no longer being available.
"It's a very well-known and common feature in everyone's life that from time to time electronic documents are lost for all kinds of reasons," he said, adding: "This is something that happens to us all that sometimes documents are lost."
The row dates back to 2019, when Mrs Rooney said she had posted fake stories online that she claimed could only have been seen by Mrs Vardy's Instagram account, and that had been leaked to The Sun newspaper.
She was later dubbed Wagatha Christie after saying she had carried out an investigation to find out who was behind the leaks.
Mrs Vardy strenuously denied being the source of the leaks and said a number of people had access to her accounts.
In a pre-trial hearing less than two weeks before the trial began, Mrs Rooney's barrister said Mrs Vardy now "appears to accept" that Ms Watt was the source of leaked stories.
Ms Watt has denied being the source and has been deemed too ill to testify.
Mrs Rooney's barrister compared Mrs Vardy's connection with Ms Watt in relation to the leaks as "like hiring a hitman or woman".
He said: "Just because you're not the person who gets their hands dirty, doesn't mean you're not equally responsible."
Mrs Vardy, he stressed, "is just as responsible" for the stories being leaked even "if she doesn't pull the trigger".
He said there had also been "numerous examples of the claimant and Ms Watt conspiring to pass private and personal information on to the press about other individuals".
But Mr Tomlinson said that if Ms Watt was the source of leaked stories, "that's not something that Mrs Vardy knew anything about" and she did not "approve of or authorise" her to do so.
He told the court that Mrs Vardy "had no choice" but to bring the libel claim against Mrs Rooney because she needed to "establish her innocence and vindicate her reputation".
Mr Tomlinson said on Tuesday that, if information had been leaked, "this was not something that was done with Mrs Vardy's knowledge or authority".
He said there was "no information" in any evidence to demonstrate that Mrs Vardy had even viewed Mrs Rooney's Instagram posts during the alleged "sting operation".
'Distressing and disturbing'
The fake stories posted by Mrs Rooney included planning her return to TV, travelling to Mexico for a "gender selection" procedure and her basement flooding.
Mr Tomlinson said the affair and subsequent libel case had garnered huge press coverage and had become a source of "entertainment" in the media.
But he added: "This is far from being an entertaining case. It has been profoundly distressing and disturbing."
Mr Tomlinson added: "[Mrs Vardy] needs to be able to clear her name through this case, so she can move on from this terrible episode."
He said that as a result of Mrs Rooney's post, Mrs Vardy - who was seven months pregnant at the time - and her family were subjected to abuse, including posts saying she should die.
With pride and reputations at stake on both sides, the onus is on the defendant, Mrs Rooney, to prove that it was in fact Mrs Vardy who leaked the stories.
Mr Sherborne, for Mrs Rooney, told the court: "She's not here because she wants to be, she's here because she has to be."
Her investigation into the leaks was "deeply upsetting" for Mrs Rooney and made her feel "paranoid", he told the court.
The celebrity civil trial - which will be decided by a judge, not a jury - is set to run for seven days.
Mrs Rooney arrived at court in a surgical boot alongside her husband - reminiscent of when Wayne injured his foot before the 2006 World Cup, the same tournament where the England "Wags" (wives and girlfriends) first exploded on to the scene.
Journalists queued to get inside a packed courtroom for this most intriguing of cases.
Mrs Vardy sat at the front left bench with her hair in a bun, wearing a blue dress, while Mrs Rooney, wearing a black jacket, sat at the front right bench.